An Ohio father said his toddler is unlikely to survive after the girl's babysitter allegedly assaulted her and left her brain dead.

Police said the babysitter, Lindsay Partin, 35, admitted to striking 3-year-old Hanna Wesche last week “and stated she had fallen and struck her head on the concrete garage floor the previous day,” according to a statement Monday.

Partin pleaded not guilty to charges of felonious assault and child endangerment in connection with the incident.

Police in Butler County, Ohio, about 35 miles north of Cincinnati, said they arrived at Partin’s home last Thursday and found the girl unresponsive, with labored breathing and "obvious bruises about her head and face."

Hanna was immediately transported to a local hospital and later flown to Cincinnati Children’s Hospital with life-threatening injuries, according to police.

"This little girl is hanging on by a thread. Cases like this rip your heart out. I don't understand why or how anyone harms a child," Butler County Sheriff Richard Jones said in a statement. "We do not know if the child will survive her injuries at this time."

Hanna’s father, Jason Wesche, said she is brain dead and unlikely to survive.

"I mean, it's unimaginable. I can't begin to explain the feeling of losing a child at the hands of this ... of just a violent act. Hannah was great," Wesche said Monday at Partin’s arraignment, according to ABC affiliate WWSB. "We just want to stress that this situation is devastating. She is not expected to survive. Within the next couple of days, we are told that it's going to come to an end."